On Thu, 23 Mar 2017, dhara buch wrote:
Hello,
I am doing profiling with command,
operf ./test --events=BR_INST_RETIRED
where test.c is a simple c language file.
then, I am trying to collect information with command
opreport --symbols --debug-info
From the documents of Oprofile, I assume that the above command lists profiling
result as per the symbols i.e. I can get result showing samples, linear info,
image name and symbol name.
As per my command I expect my file name (test.c) to be in the linear info and
image name, but shows [no location information] in linear info. The filename
does not get listed in image
name also.
What is lacking?
Hi, I think you need to rebuild the test with '-g' switch.
If the test binary does not have debuginfo, opreport cannot
resolve that.
Me trying with debuginfo:
samples % linenr info image name symbol
name
10 66.6667 (no location information) no-vmlinux
/no-vmlinux
2 13.3333 exact_counts.c:13 exact_counts main
1 6.6667 exact_counts.c:10 exact_counts f_65535x
1 6.6667 exact_counts.c:9 exact_counts f_997x
1 6.6667 (no location information) ld-2.17.so _dl_fini
And without:
samples % linenr info image name symbol
name
10 55.5556 (no location information) no-vmlinux
/no-vmlinux
3 16.6667 (no location information) exact_counts f_65535x
2 11.1111 (no location information) exact_counts main
1 5.5556 (no location information) ld-2.17.so
_dl_add_to_slotinfo
1 5.5556 (no location information) ld-2.17.so
_dl_next_tls_modid
1 5.5556 (no location information) ld-2.17.so
_dl_relocate_object
Is this the problem you are asking about?
I tried to set vmlinux with operf --vmlinux option also where vmlinux file in
in /usr/lib/debug/lib/4*/vmlinux, still the above commands do not list test
file entries.
The "--vmlinux" option is there for enabling this for samples
obtained in kernelspace.
By default (assuming you have no kernel debuginfo available),
operf marks all the samples taken in kernel (e.g. your program
called a syscall and the sample was taken when the syscall was
being executed or you profile systemwide) as "no-vmlinux".
This is sufficient if you care about userspace only and not about
the "time" spent in kernel.
If you care about kernelspace, you need the '--vmlinux' option
with correct path specified.
What is lacking?
Thank you,
Dhara buch
Has this helped?
Cheers,
Michael
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